/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    RemoveRange.java
 *    Copyright (C) 1999-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.instance;

import java.util.Enumeration;
import java.util.Vector;

import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.Range;
import weka.core.Utils;
import weka.core.WeightedAttributesHandler;
import weka.core.WeightedInstancesHandler;
import weka.filters.Filter;
import weka.filters.UnsupervisedFilter;

/**
 * <!-- globalinfo-start --> A filter that removes a given range of instances of
 * a dataset.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -R &lt;inst1,inst2-inst4,...&gt;
 *  Specifies list of instances to select. First and last
 *  are valid indexes. (required)
 * </pre>
 * 
 * <pre>
 * -V
 *  Specifies if inverse of selection is to be output.
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Eibe Frank (eibe@cs.waikato.ac.nz)
 * @version $Revision$
 */
public class RemoveRange extends Filter implements UnsupervisedFilter, OptionHandler, WeightedAttributesHandler, WeightedInstancesHandler {

    /** for serialization */
    static final long serialVersionUID = -3064641215340828695L;

    /** Range of instances requested by the user. */
    private final Range m_Range = new Range("first-last");

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {

        Vector<Option> newVector = new Vector<Option>(2);

        newVector.addElement(new Option("\tSpecifies list of instances to select. First and last\n" + "\tare valid indexes. (required)\n", "R", 1, "-R <inst1,inst2-inst4,...>"));

        newVector.addElement(new Option("\tSpecifies if inverse of selection is to be output.\n", "V", 0, "-V"));

        return newVector.elements();
    }

    /**
     * Parses a given list of options.
     * <p/>
     * 
     * <!-- options-start --> Valid options are:
     * <p/>
     * 
     * <pre>
     * -R &lt;inst1,inst2-inst4,...&gt;
     *  Specifies list of instances to select. First and last
     *  are valid indexes. (required)
     * </pre>
     * 
     * <pre>
     * -V
     *  Specifies if inverse of selection is to be output.
     * </pre>
     * 
     * <!-- options-end -->
     * 
     * @param options the list of options as an array of string.s
     * @throws Exception if an option is not supported.
     */
    @Override
    public void setOptions(String[] options) throws Exception {

        String str = Utils.getOption('R', options);
        if (str.length() != 0) {
            setInstancesIndices(str);
        } else {
            setInstancesIndices("first-last");
        }
        setInvertSelection(Utils.getFlag('V', options));

        if (getInputFormat() != null) {
            setInputFormat(getInputFormat());
        }

        Utils.checkForRemainingOptions(options);
    }

    /**
     * Gets the current settings of the filter.
     * 
     * @return an array of strings suitable for passing to setOptions.
     */
    @Override
    public String[] getOptions() {

        Vector<String> options = new Vector<String>();

        if (getInvertSelection()) {
            options.add("-V");
        }
        options.add("-R");
        options.add(getInstancesIndices());

        return options.toArray(new String[0]);
    }

    /**
     * Returns a string describing this filter
     * 
     * @return a description of the filter suitable for displaying in the GUI.
     */
    public String globalInfo() {

        return "A filter that removes a given range of instances of a dataset.";
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String instancesIndicesTipText() {

        return "The range of instances to select. First and last are valid indexes.";
    }

    /**
     * Gets ranges of instances selected.
     * 
     * @return a string containing a comma-separated list of ranges
     */
    public String getInstancesIndices() {

        return m_Range.getRanges();
    }

    /**
     * Sets the ranges of instances to be selected. If provided string is null,
     * ranges won't be used for selecting instances.
     * 
     * @param rangeList a string representing the list of instances. eg:
     *                  first-3,5,6-last
     * @throws IllegalArgumentException if an invalid range list is supplied
     */
    public void setInstancesIndices(String rangeList) {

        m_Range.setRanges(rangeList);
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String invertSelectionTipText() {

        return "Whether to invert the selection.";
    }

    /**
     * Gets if selection is to be inverted.
     * 
     * @return true if the selection is to be inverted
     */
    public boolean getInvertSelection() {

        return m_Range.getInvert();
    }

    /**
     * Sets if selection is to be inverted.
     * 
     * @param inverse true if inversion is to be performed
     */
    public void setInvertSelection(boolean inverse) {

        m_Range.setInvert(inverse);
    }

    /**
     * Returns the Capabilities of this filter.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enableAllAttributes();
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Sets the format of the input instances.
     * 
     * @param instanceInfo an Instances object containing the input instance
     *                     structure (any instances contained in the object are
     *                     ignored - only the structure is required).
     * @return true because outputFormat can be collected immediately
     * @throws Exception if the input format can't be set successfully
     */
    @Override
    public boolean setInputFormat(Instances instanceInfo) throws Exception {

        super.setInputFormat(instanceInfo);
        setOutputFormat(instanceInfo);
        return true;
    }

    /**
     * Input an instance for filtering. Filter requires all training instances be
     * read before producing output.
     * 
     * @param instance the input instance
     * @return true if the filtered instance may now be collected with output().
     * @throws IllegalStateException if no input structure has been defined
     */
    @Override
    public boolean input(Instance instance) {

        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }
        if (m_NewBatch) {
            resetQueue();
            m_NewBatch = false;
        }
        if (isFirstBatchDone()) {
            push(instance);
            return true;
        } else {
            bufferInput(instance);
            return false;
        }
    }

    /**
     * Signify that this batch of input to the filter is finished. Output() may now
     * be called to retrieve the filtered instances.
     * 
     * @return true if there are instances pending output
     * @throws IllegalStateException if no input structure has been defined
     */
    @Override
    public boolean batchFinished() {

        if (getInputFormat() == null) {
            throw new IllegalStateException("No input instance format defined");
        }

        if (!isFirstBatchDone()) {
            // Push instances for output into output queue
            m_Range.setUpper(getInputFormat().numInstances() - 1);
            for (int i = 0; i < getInputFormat().numInstances(); i++) {
                if (!m_Range.isInRange(i)) {
                    push(getInputFormat().instance(i), false); // No need to copy
                }
            }
        } else {
            for (int i = 0; i < getInputFormat().numInstances(); i++) {
                push(getInputFormat().instance(i), false); // No need to copy
            }
        }

        flushInput();

        m_NewBatch = true;
        m_FirstBatchDone = true;

        return (numPendingOutput() != 0);
    }

    /**
     * Main method for testing this class.
     * 
     * @param argv should contain arguments to the filter: use -h for help
     */
    public static void main(String[] argv) {
        runFilter(new RemoveRange(), argv);
    }
}
